TY - JOUR
T1 - Remote sensing of euphotic depth in shallow tropical inland waters of Lake Naivasha using MERIS data
AU - Majozi, N.P.
AU - Salama, M.S.
AU - Bernard, Stewart
AU - Harper, David M.
AU - Habte, Mussie Ghirmai
PY - 2014
Y1 - 2014
N2 - Freshwater resources are deteriorating rapidly due to human activities and climate change. Remote sensing techniques have shown potential for monitoring water quality in shallow inland lakes, especially in data-scarce areas. The purpose of this study was to determine the spectral diffuse attenuation coefficient (Kd(λ)) of the water column, in order to map the euphotic depth (Zeu) of Lake Naivasha, Kenya using the Medium Resolution Imaging Spectrometer (MERIS). Intensive in situ radiometric and limnological data collection was undertaken at Lake Naivasha. Atmospheric correction was done on the MERIS images using MERIS Neural Network algorithms, Case 2 Waters (C2R) and Eutrophic Lakes processors and the bright pixel atmospheric correction algorithm (BPAC). The Eutrophic Lakes processor gave the most accurate atmospherically corrected remote sensing reflectances at 490 nm compared to the other processors, with mean absolute percentage error (MAPE) of 47% and a root mean square error (RMSE) 43%, with BPAC giving negative reflectances in the blue spectral range. In situ Kd and Zeu models were calibrated and validated using above- and under-water radiometric measurements, and tested on the Neural Network atmospheric correction processed MERIS images. The Eutrophic Lakes estimates were the most accurate, with an RMSE of 0.26 m− 1 and MAPE of 18% for Kd(490) and RMSE of 0.17 m and MAPE of 14% for Zeu. The Zeu maps produced from MERIS images clearly show the variation of euphotic depth both in space and time. These results indicate the suitability of MERIS to monitor euphotic depth and other water quality parameters of shallow inland water bodies.
AB - Freshwater resources are deteriorating rapidly due to human activities and climate change. Remote sensing techniques have shown potential for monitoring water quality in shallow inland lakes, especially in data-scarce areas. The purpose of this study was to determine the spectral diffuse attenuation coefficient (Kd(λ)) of the water column, in order to map the euphotic depth (Zeu) of Lake Naivasha, Kenya using the Medium Resolution Imaging Spectrometer (MERIS). Intensive in situ radiometric and limnological data collection was undertaken at Lake Naivasha. Atmospheric correction was done on the MERIS images using MERIS Neural Network algorithms, Case 2 Waters (C2R) and Eutrophic Lakes processors and the bright pixel atmospheric correction algorithm (BPAC). The Eutrophic Lakes processor gave the most accurate atmospherically corrected remote sensing reflectances at 490 nm compared to the other processors, with mean absolute percentage error (MAPE) of 47% and a root mean square error (RMSE) 43%, with BPAC giving negative reflectances in the blue spectral range. In situ Kd and Zeu models were calibrated and validated using above- and under-water radiometric measurements, and tested on the Neural Network atmospheric correction processed MERIS images. The Eutrophic Lakes estimates were the most accurate, with an RMSE of 0.26 m− 1 and MAPE of 18% for Kd(490) and RMSE of 0.17 m and MAPE of 14% for Zeu. The Zeu maps produced from MERIS images clearly show the variation of euphotic depth both in space and time. These results indicate the suitability of MERIS to monitor euphotic depth and other water quality parameters of shallow inland water bodies.
KW - ITC-ISI-JOURNAL-ARTICLE
KW - 2024 OA procedure
U2 - 10.1016/j.rse.2014.03.025
DO - 10.1016/j.rse.2014.03.025
M3 - Article
SN - 0034-4257
VL - 148
SP - 178
EP - 189
JO - Remote sensing of environment
JF - Remote sensing of environment
ER -